Air compressor



FIG. 1 is a perspective view of an ornamental design for an air compressor;

FIG. 2 is a perspective view of an ornamental design for an air compressor showing a cover in a raised position;

FIG. 3 is a perspective view of an ornamental design for an air compressor showing a handle in a raised position;

FIG. 4 is a front and top view of an ornamental design for an air compressor;

FIG. 5 is a left side view of an ornamental design for an air compressor; and,

FIG. 6 is a right side view of an ornamental design for an air compressor.

It being understood that the broken lines are for illustrative purposes only and form no part of the claimed design. 

The design for an air compressor, as shown and described. 